Measuring distances to high accuracy is typically an important function in a wide range of fields, such as machine tools, manufacturing, automotive, and construction. Conventional measurement devices, however, have various limitations. For example, linear scales devices, which use incremental encoding, are typically required to be attached to an object being measured, and have relatively tight alignment requirements. In addition, conventional laser interferometers are typically bulky and expensive.
To improve measurement, conventional time-of-flight lasers have been used. One such approach is fine-grained time-base measurement, which, for example, can be on the order of tens of picoseconds, and statistical sampling of many trials can increase resolution. However, this approach is limited by the time resolution. Another time-of-flight approach is the Fizeau method, which measures distance via a phase locked loop (PLL) locking to a beat-frequency. A drawback associated with this approach is that it has a relatively long convergence time, and is sensitive to variations in distance. Another drawback with the conventional approach is that conventional measuring devices are typically less flexible, and they are typically required to operate in control environments such as a laboratory or a testing center.